Organic polymers containing at least one reactive silicon group in a molecule are known to crosslink even at room temperature by the formation of a siloxane bond accompanying hydrolysis of the reactive silicon group due to moisture etc., and the like, to produce a rubbery cured product.
Of these polymers having a reactive silicon group, a polymer wherein the main chain skeleton is a polyoxyalkylene polymer or a polyisobutylene polymer is disclosed in patent reference 1, patent reference 2 and the like, has been industrially produced and widely used as sealing material, adhesive, paint and the like.
Curable compositions used for sealing materials, adhesives, paints and the like and rubbery cured products obtained by curing are requested to show various properties such as curability, adhesiveness, mechanical property and the like and various investigations are underway.
As a reactive silicon group, for example, a polymer having a silicon group, wherein two hydrolyzable groups are bonded per one silicon atom, affords a composition superior in elongation and flexibility. As disclosed in patent reference 3, patent reference 4 and the like, a polymer having a silicon group, wherein three hydrolyzable groups are bonded per one silicon atom, has superior curability.
Patent reference 5, patent reference 6 and patent reference 7 describe control of adhesiveness, tensile property of cured product and the like by the addition of amino group-substituted alkoxysilane.
A curable composition containing an organic polymer having a reactive silicon group is cured with a silanol condensation catalyst and, generally, organotin catalysts having a carbon-tin bond such as dibutyltinbis(acetylacetonate) and the like have been widely used. In recent years, however, the toxicity of organotin compounds has been pointed out and the development of a non-organotin catalyst is desired.
As described in patent reference 8, patent reference 9, patent reference 10, patent reference 11, patent reference 12 and patent reference 13, tin carboxylates and other metal carboxylates can also be used as a silanol condensation catalyst. These prior art references have already disclosed that curability is improved by a combined use of metal carboxylate and an amine compound.
patent reference 1: JP-A-52-73998
patent reference 2: JP-A-63-6041
patent reference 3: WO98/47939
patent reference 4: JP-A-2000-129126
patent reference 5: JP-A-2000-345054
patent reference 6: JP-A-5-117519
patent reference 7: JP-B-62-35421
patent reference 8: JP-A-55-9669
patent reference 9: JP-B-3062626
patent reference 10: JP-A-6-322251
patent reference 11: JP-A-2000-345054
patent reference 12: JP-A-2003-206410
patent reference 13: JP-A-2002-285018